1. Field of the Invention
The present invention relates to a so-called front-opening interface mechanical standard (FIMS) system, that is, a load port apparatus, which is used for transferring, from one semiconductor processing apparatus to another semiconductor processing apparatus, wafers held in a sealed-type transport container called a pod, or for transferring the wafers from the semiconductor processing apparatus to the pod, during a semiconductor manufacturing process and the like. Further, the present invention relates to a clamping device to be used for the load port apparatus when fixing the pod onto the load port apparatus.
2. Description of the Related Art
In recent years, in a general semiconductor manufacturing process, cleanliness is managed throughout the entire process by maintaining a highly clean state in only the following three spaces: inner spaces of various processing apparatus; an inner space of a pod capable of containing wafers and transporting the wafers from one processing apparatus to another processing apparatus; and a mini-environment in which the wafers are exchanged between the pod and the respective processing apparatus. Such a pod includes a main-unit portion which contains wafers therein and which has a wafer-insertion-and-removal opening formed in one side surface, and a lid which makes the inside of the pod serve as a sealed space by closing the opening. Further, a structure that defines the mini-environment includes an opening portion capable of facing the above-mentioned opening of the pod and a second opening portion arranged on the semiconductor processing apparatus side so as to face the opening portion.
The load port apparatus includes a member as a partition wall provided with the opening portion, that is, a wall called a side base, a door for closing the opening portion, a door drive mechanism for controlling operation of the door, and a mount base on which the pod is to be mounted. The mount base is capable of supporting the pod in such a manner that the opening of the pod and the opening portion face each other, and moving so as to bring the lid of the pod close to or apart from the door together with the pod itself. The door is capable of holding the lid of the pod. The door drive mechanism causes the door to open and close the opening portion under a state of holding the lid, and the door is caused to retract below a space between the opening portion and the second opening portion or to enter the space. A robot is arranged in the mini-environment, and the robot is capable of entering into and retracting from the inside of the pod through the opening portion and the opening of the pod, and transfers wafers between the inside of the pod and the semiconductor processing apparatus also through the second opening portion.
On the above-mentioned mount base, there is arranged a configuration for fixing the pod onto the mount base so as to prevent displacement of the mounted pod from a predetermined mount position at the time when the mount base is moved. For example, Japanese Patent Application Laid-Open No. 2005-209986 discloses a clamping unit for fixing the pod by protruding, after the pod is mounted, from a surface of the mount base, entering an engagement depression provided in a bottom surface of the pod, and engaging with a surface to be clamped, which is provided in the engagement depression. Further, Japanese Patent Application Laid-Open No. 2006-114699 discloses a clamping device, which is originally arranged in the surface of the mount base so as to protrude therefrom, and engages with the surface to be clamped of the engagement depression through a pivoting operation. Further, Japanese Patent Application Laid-Open No. 2002-164412 discloses a wafer transporting container mounting device including a mechanism in which, after the pod is mounted, a clamping portion protruding from the surface of the mount base engages with the surface to be clamped.
In the semiconductor manufacturing process, the use of wafers each having a larger diameter has been progressed for the purpose of productivity improvement or the like. Therefore, as the above-mentioned pod, mini-environment, and internal space of the processing apparatus, the use of a larger pod, mini-environment, and internal space has been progressed as well. In view of the above-mentioned pod clamping configuration of the conventional technology, the portion to be clamped is arranged in the bottom surface of the pod, and is provided as a plate-like member extending in parallel to the bottom surface of the pod. At the time of actually fixing and clamping the pod, the clamping portion applies, to the plate-like member, a load for urging the plate-like member vertically downward. When the pod is upsized, an inertial force generated when the pod is moved is also increased, and in order to resist the inertial force, the load applied by the clamping portion to the portion to be clamped is inevitably increased.
In the aspect of the pod configuration, the increase in thickness of the plate-like part of the portion to be clamped leads to increase in weight of the pod or in size of the configuration of the bottom portion of the pod, and thus it may be difficult to allow such increase in thickness. However, as described above, the load generated by the clamping portion is also inevitably increased, and hence, in the conventional configuration, the plate-like portion to be clamped may be deformed due to the increased load. Therefore, there is a demand for development of a clamping mechanism capable of achieving both increase in load and suppression of deformation of the portion to be clamped, which have originally been trade-off conditions.